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I I I March 2006 3 053-2442 collected from the push probes were submitted for laboratory analysis of petroleum hydrocarbon constituents and VOCs. Analytical results indicated groundwater near the former tank basin contained concentrations of chlorinated solvents, with tetrachloroethene concentrations ranging from 2.6 to 220 micrograms per liter (J.lg/I). This information was reported to MPCA in a letter from Foth & Van Dyke to Mr. Dave Holst of MPCA dated April 1 7, 1997. I I I 1.3.4 Phase I Environmental Site Assessment (2004) Braun Intertec Corporation (Braun) conducted a Phase I Environmental Site Assessment (ESA) of the property during September 2004. The Phase I ESA report identified the following recognized environmental conditions at the site: I I . Former presence of a printing facility on-site and unknown use of the site prior to the 1950s. . Documentation of VOC-impacted groundwater. . Use of the western portion of the on-site structure as a maintenance shop. . Former presence of a leaking UST containing fuel oil. . Historical use of an on-site septic system. 1.3.5 Phase II Environmental Site Assessment (February 2005) I I I I I Braun conducted a limited Phase II ESA at the subject property during February 2005 to further evaluate potential environmental impacts associated with recognized environmental conditions identified during completion of the Phase I ESA. The Phase II ESA involved advancing 15 push probes at the site (probes GP-l through GP-15, Figure 2) to depths of approximately 12 feet below ground surface, and analyzing 14 soil and seven groundwater samples collected from the push probes for VOCs and petroleum hydrocarbon constituents. One soil sample, collected at a depth of one to two feet below ground surface from an area just east of the First Addition (probe GP-4, Figure 2), contained tetrachloroethene at a concentration of 0.18 milligrams per kilogram (mg/kg). VOCs were not measured at detectable concentrations in any of the other 13 soil samples collected at that time. I I I I I I Chlorinated organic compounds were measured at detectable concentrations in two of the seven shallow groundwater samples collected at the site. Specifically, 1,2-dichloroethene, trichloroethene, and tetrachloroethene were measured at concentrations 2.2, 20, and 270 J.lg/I, respectively, in the groundwater sample collected from just east of the First Addition (probe GP-4, Figure 2). A groundwater sample collected approximately 75 feet directly east of the main entrance to the office building (probe GP-l1, Figure 2) contained 1,2-dichloroethene, tricholorethene, and tetrachloroethene at concentrations of 260, 110, and 310 J.lg/I, respectively. This groundwater sample also contained gasoline range organics at a concentration of 240 J.lg/l. In their Phase II ESA report Braun recommended that additional investigative work be completed at the site to further delineate the extent and magnitude of soil and groundwater impacted by chlorinated solvents. Braun also recommended that the site be enrolled in MPCA's VIe program. 1.3.6 Supplemental Phase II Environmental Site Assessment (September 2005) Braun completed a Supplemental Phase II ESA during July 2005 to "further evaluate the extent and magnitude of groundwater contaminated by chlorinated hydrocarbons identified during the previous Phase II ESA." The Supplemental Phase II ESA involved advancing an additional 19 push probes at the site (probes GP-16 through GP-34, Figure 2), including two through the concrete floor of the